Flow visualization techniques for full-scale test objects in a wind tunnel: Evaluation of a novel flow visualization technique

Abstract

Accurate flow visualization in wind tunnels is essential for aerodynamic optimization and CFD validation. Traditional qualitative methods such as smoke and tufts offer quick insights but lack quantitative precision. Conversely, techniques like Laser Doppler Anemometry (LDA) and Particle Image Velocimetry (PIV) provide detailed flow measurements but involve complex setups and pose safety concerns due to high-powered lasers. This thesis identifies the ProCap system as a measurement system that bridges this gap by providing qualitative and quantitative information with relatively low complexity. ProCap measurements around a full-scale car in a commercial wind tunnel are compared against an existing pressure-based traversegear system and CFD simulations. The findings show that ProCap is not sufficiently accurate or consistent for CFD method validation, but can be a valuable tool when evaluating vehicle designs by identifying separated regions and overall flow topology.